“Mayor Bloomberg has a solid and strong and enthusiastic base of support,” Bernie Sanders said from the debate stage in South Carolina Tuesday night. “Problem is, they’re all billionaires.”

It was a tidy one-liner (with the bonus that it happens to have a basis in reality: Jeff Bezos was among those who reportedly lobbied the former New York mayor to get in the race), but the joke was met, somewhat mystifyingly, by a loud round of boos from the debate-night crowd in South Carolina.

The same crowd had, for most of the night, been enthusiastically erupting at a noticeable volume for every answer Michael Bloomberg gave — including when he very nearly admitted that he “bought” 21 new members of Congress in 2018.

According to WCSC, the CBS affiliate in Charleston, the only way to secure a ticket to the debate hosted by the DNC, the Black Caucus Institute, CBS, and Twitter, was “to become a sponsor” — at costs that ranged from $1,750 to $3,200.

An unnamed Bloomberg official denied to NBC News that the campaign had paid for tickets to the event.

But one can easily see where the confusion might come from — according to a recent Wall Street Journal report, the Bloomberg campaign is paying more than 500 people — “deputy digital organizers” they’re calling them — up to $2,500 a month to hype Mike Bloomberg by text and on their personal social media accounts. (The results of that investment, according to the Los Angeles Times, have been … mixed.)

Charleston County Democratic Party Chair Colleen Condon told WCSC the “tickets are first handed out to organizers. Then, campaigns may get some tickets to disperse among supporters.”

Bloomberg, who has yet to compete in a single contest, already has spent more than any primary campaign in history: in excess of $500 million as of Friday, or roughly $5.5 million a day.